Control system and method for laser pump of doped fiber amplifier

ABSTRACT

A control system includes a field-programmable gate array (FPGA), a digital-to-analog conversion (DAC) circuit, an external TEC driver, and a pump chip. The field-programmable gate array (FPGA) includes a pump driver and a thermoelectric-cooler (TEC) controller. The digital-to-analog conversion (DAC) circuit is coupled to the FPGA. The external TEC driver is external to the FPGA and coupled to the FPGA. The pump chip includes a pump and a TEC and is coupled to the DAC circuit and the external TEC driver.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese Patent Application No.201911369224.9 filed on Dec. 26, 2019, the content of which is reliedupon and incorporated herein by reference in its entirety.

TECHNICAL FIELD

The disclosure relates generally to the field of control technology fora doped fiber amplifier, such as an erbium doped fiber amplifier (EDFA),in particular to a control structure and control method foruninterrupted light output of such a doped fiber amplifier.

BACKGROUND

In an erbium-doped fiber amplifier (EDFA) control system, when thesystem is running or during maintenance, it is crucial to maintain astable output of the light-drive pump. Many existing EDFA controlsystems use modes in which a field-programmable gate array (FPGA)directly drives the pump. However, for structures that use direct-drivemodes for the EDFA pump, output light may be interrupted when the FPGAis being upgraded because the FPGA may not maintain the output.Therefore, the operation may be influenced.

As an example, FIG. 1 illustrates a schematic diagram of an existingEDFA control system according to the prior art. The EDFA control systemof FIG. 1 includes a FPGA 110, a digital-to-analog conversion (DAC)circuit 120, and a pump chip 140. The FPGA 110 includes a pump driver111, a TEC controller 115, and a TEC driver 116 in the FPGA 110. Thepump chip 140 includes a pump 141 and a thermoelectric-cooler (TEC) 142.During the updating of the FPGA 110, the FPGA 110 may not maintain theoutput. Accordingly, output light may be interrupted, and the tasks oroperations may be influenced.

The subject matter of the present disclosure is directed to overcoming,or at least reducing the effects of, one or more of the problems setforth above.

SUMMARY

The present disclosure provides control systems and control methods foran uninterrupted light output of a doped fiber amplifier, such as anerbium doped fiber amplifier (EDFA).

In some examples, a control system includes a field-programmable gatearray (FPGA), a digital-to-analog conversion (DAC) circuit, an externalTEC driver, and a pump chip. The field-programmable gate array (FPGA)includes a pump driver and a thermoelectric-cooler (TEC) controller. Thedigital-to-analog conversion (DAC) circuit is coupled to the FPGA. Theexternal TEC driver is external to the FPGA and coupled to the FPGA. Thepump chip includes a pump and a TEC and is coupled to the DAC circuitand the external TEC driver.

In certain examples, A control system, includes a primaryfield-programmable gate array (FPGA), a backup FPGA, a digital-to-analogconversion (DAC) circuit, and a pump chip. The FPGA includes a pumpdriver, a thermoelectric-cooler (TEC) controller, and a TEC driver. Thebackup FPGA includes a pump driver, a TEC controller, and a TEC driver.The digital-to-analoc conversion (DAC) circuit is coupled to the primaryand backup FPGAs. The pump chip includes a pump and a TEC and is coupledto the DAC circuit and the primary and backup FPGAs.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be further described in detail below withreference to embodiments and accompanying drawings in which:

FIG. 1 illustrates a schematic diagram of an existing control systemaccording to the prior art for an EDFA;

FIG. 2A illustrate portion of a doped fiber amplifier according to thepresent disclosure;

FIG. 2B illustrates a schematic diagram of an example control system fora doped fiber amplifier, such as an EDFA, including a FPGA foruninterrupted light output according to disclosed embodiments;

FIG. 3 illustrates a schematic diagram of another example control systemfor a doped fiber amplifier, such as an EDFA, including multiple FPGAsfor uninterrupted light output according to disclosed embodiments;

FIG. 4 illustrates a flow chart of an example control method 400 for anexample EDFA control system including a FPGA for uninterrupted lightoutput according to disclosed embodiments; and

FIG. 5 illustrates a flow chart of an example control method 500 for anexample EDFA control system including multiple FPGAs for uninterruptedlight output according to disclosed embodiments.

DETAILED DESCRIPTION

FIG. 2A schematically illustrate portion of one type of doped fiberamplifier 50 according to the present disclosure. In the doped fiberamplifier 50, an optical signal S is transmitted along a fiber 52 and ispassed through a doped fiber 58, which is doped with a rare-earthelement, such as erbium or the like. At the same time, ions in the dopedfiber 58 are energized using pump light P, which is provided by a laserpump laser 240 at a different wavelength.

For example, the optical signal S transmitted along the fiber 52 passesan isolator 54, which reduces back reflection. The laser pump 240injects pump light P into the fiber 52 using a beam combiner 56. Thepump light P energizes ions in the doped fiber 58. Meanwhile, in thedoped fiber 58, photons of the optical signal S interact with theenergized ions, causing the ions to give up some of their energy in theform of photons at the same wavelength as the photons of the opticalsignal S, with the ions returning to a lower energy state. The opticalsignal S is thereby amplified as it passes through the doped fiber 58 toproduce an amplified signal S_(A). As an Erbium doped fiber amplifier(EDFA), the optical signal S to be amplified can be in the 1550-nmwavelength range, and the wavelength of the pump light P from the pumplaser 240 can be 980 and/or 1480 nm. As shown, the laser pump 240 can becontrolled by a control system 200, which includes one or more fieldprogrammable arrays (FPGAs) 210 and can include a memory 205. Thecontrol system 200 is directed to a Non-Traffic-Affection (NTA) hardwarecontrol system or structure, which may include a controlsystem/structure based on a single FPGA 210; or a controlsystem/structure based on multiple FPGAs 210, such as dual FPGAs, Whenupgrading certain components of the NTA hardware control system 200, thetasks or operations may not be affected or interrupted, or interruptionto the tasks or operations may be reduced. The control system 200 may bechosen according to various application scenarios.

In one embodiment, the control system 200 has a single FPGA 210 toachieve an uninterrupted light output of the laser pump 240 for thedoped fiber amplifier 50 (e.g., EDFA). In the NTA control system 200having the single FPGA 210, the driving part of thermoelectric-cooler(TEC) control-and-drive components originally located inside the FPGA210 may be moved to the outside of the FPGA 210, and the control system200 can use a thermoelectric-cooler (TEC) controller, such as acommercially available TEC controller, to maintain a temperature of thedrive pump in a configured or preset range during the FPGA upgrade. TheFPGA 210 as disclosed herein may be, for example, a FPGA circuit.

Turning to further details, FIG. 2B illustrates a schematic diagram ofan example control system 200 of the present disclosure for a dopedfiber amplifier, such as described in FIG. 2A. The control system 200includes a single FPGA 210 for uninterrupted light output according todisclosed embodiments. In addition to the single FPGA 210, the controlsystem 200 includes a digital-to-analog conversion (DAC) circuit 220, anexternal TEC driver (e.g., an external TEC drive 230 that is externalwith respect to the FPGA 210). The FPGA 210 includes a pump driver 211and a TEC controller 215 integrated in the FPGA 210. The laser pumpbeing controlled by the control system 200 has a pump chip 240 thatincludes a pump 241 and a thermoelectric-cooler (TEC) 242 integrated inthe pump chip 240.

An output terminal 212 of pump driver 211 is coupled to an inputterminal 221 of the DAC circuit 220. and an output terminal 222 of theDAC circuit 220 is coupled to the pump 241 that is integrated in thepump chip 240. An output terminal 216 of the TEC controller 215 iscoupled to die external TEC driver 230 that is external to the FPGA 210or outside the FPGA 210. For example, the output terminal 216 of the TECcontroller 215 is coupled to an input terminal 231 of the external TECdriver 230. An output terminal 232 of the external TEC driver 230 iscoupled to the TEC 242 integrated in the pump chip 240.

As noted above, the control system 200 may further include a memory 205,such as a memory inside or outside the FPGA 210, In some examples, thememory 205 may include a non-volatile or volatile memory external to theFPGA 210; and/or anon-volatile memory in the FPGA 210; and/or any othersuitable memory device for storing data of the FPGA 210 during upgradingthe FPGA 210, such as configuration data of the FPGA 210.

As will be appreciated, the arrangement depicted in FIG. 2 is merelyschematic. The pump chip 240 can have one or more pumps 241 and can haveone or more TEC devices 242 depending on the implementation. The controlsystem 200 can be configured to operate the one or more pumps 241 andTEC devices 242 as needed.

In some examples, the pump driver 211 is configured to drive the pump241 to produce optical output for a doped fiber amplifier; the TECcontroller 215 is configured to control the TEC 242 to adjust atemperature of at least a portion of the pump chip 240; and the externalTEC driver 230 is configured to control the TEC 242 in place of the TECcontroller 215.

In some examples, the FPGA 210 has an operation mode and an update mode;the pump driver 211 is configured in the operation mode to drive thepump 241 and to be at least paused in the update mode; and the TECcontroller 215 is configured in the operation mode to control the TEC242 and be at least paused in the update mode. The DAC circuit 220 isconfigured in the operation mode to convert the drive from the pumpdriver 211 to the pump 241 and is configured in the update mode tomaintain the drive to the pump 241 for the paused pump driver 211. Incertain examples, the external TEC driver 230 is configured in theoperation mode to drive the TEC 242 based on the control of the TECcontroller 215, and is configured in the update mode to control the TEC242 for the paused TEC controller 215.

FIG. 4 illustrates a flow chart of an example control method 400 for anexample EDFA control system, such as shown in FIG. 2, including a FPGAfor uninterrupted light output according to disclosed embodiments. Viathe control method 400, light output may be uninterrupted, e.g., duringthe upgrade on a FPGA. The control method 400 may be performed by acontrol system/structure consistent with the present disclosure, such asthe above described control system 200 in FIG. 2. Accordingly,descriptions for the method 400 are made below with reference to FIGS. 2and 4.

At S401 in FIG. 4, the pump driver 211 is paused, and driver values ofthe pump 241 are kept the same. For example, the pump driver 211 in theFPGA 210 is paused, and driver values are kept the same, e.g., in theDAC 220.

At S402, the FGPA 210 stops updating the external TEC driver 230. Forexample, the FGPA 210 may stop updating, e.g., values or data, from theFGPA 210 to the external TEC driver 230; and the external TEC driver 230may take over or take the control on the TEC 242, so as to maintain thetemperature of the drive pump 241 in a configured or preset range duringthe upgrade/update of the FPGA 210.

At S403, field content (e.g., field data) of the FPGA 210 are stored toa memory 205, such as an internal non-volatile memory, an externalnon-volatile memory with respect to the FPGA 210, and/or an externalvolatile memory with respect to the FPGA 210. The external non-volatilememory (as an example of memory 205) may include, for example, anexternal flash-memory device of the control system 200. For example, thefield content of the FPGA 210 may be saved to a non-volatile memory 205that is external to the FPGA 210 and included in the control system 200.The field content of an FPGA 210 may include, for example, present pumpcontrol values and drive values, TEC control values, and/or other valuesthat need to be maintained or stored, such asvariable-optical-attenuator (VOA) settings or configuration values.

At S404, the FPGA reconfiguration is activated or performed according tothe update. During the FPGA reconfiguration, a pin, alternatively atleast one pin, or alternatively all of the IO pins (PIN) (depending onthe configuration) for FPGA 210 are kept at weak pull-up, e.g,, a weakpull-up status, and no update or refreshing is performed on the drivervalue of the pump 241, e.g., in the DAC 220. In some examples, the FPGAreconfiguration may be activated or performed by using anothercomponent, e.g., a microcontroller unit (MCU), of control system 200.

At S405, the field content is restored to the FPGA 210. For example, thefield content or field data stored in the memory 205 is restored to theFPGA 210.

At S406, the control on the TEC 242 is returned to the FPGA 210. Forexample, the control on the TEC 242 is returned from the external TECdriver 230 to the FPGA 210; and the FPGA 210 may control the TEC 242 viathe external TEC driver 230.

At S407, update of driver values for the pump 241 is activated orperformed. For example, the pump driver 211 in the FPGA 210 may resumeoperation, and the driver values for the pump 241 in the DAC 220 may beupdated by the pump driver 211.

As already noted, the non-volatile memory 205 may include, for example,an external non-volatile memory, such as an external flash memorydevice, that is external to the FPGA 210, or an internal non-volatilememory in the FPGA 210. The field content of the FPGA 210 may include,for example, present pump control values, pump drive values (i.e., pumpdriver values) such at voltage and current values, TEC control values,variable-optical-attenuator (VOA) settings or configuration values.

In contrast to the arrangement in FIG. 2, the present disclosure furtherprovides another control system or structure having multiple FPGAs, suchas dual FPGAs, to achieve an uninterrupted light output of a doped fiberamplifier (e.g., EDFA). The control system may include, for example, oneor more primary FPGAs (i.e., one or more primary driving FPGAs) and oneor more backup FPGAs (i.e., one or more backup driving FPGAs), Thecontrol system may use a control FPGA as a backup FPGA. During thereconfiguration of the primary FPGA, the backup FPGA may take over ortake control on the pump and TEC tasks. Meanwhile, the backup FPGA mayacts as a fast configuration controller, e.g., a fast-passive-parallel(FPP) configuration controller, so as to achieve fast FPGAreconfiguration.

For example, FIG. 3 illustrates a schematic diagram of another exampleEDFA control system 300 including multiple FPGAs 310, 350 foruninterrupted light output according to disclosed embodiments. Thecontrol system 300 includes a primary driving FPGA 310 (e.g., a masterFPGA), a backup driving FPGAs 350 (e.g., a slave FPGAs), a DAC circuit320, an external TEC driving circuit or an external conversion circuit399, and a pump chip 340. The external conversion circuit 399 isexternal to the primary and backup driving FPGAs (310, 350). Forexample, the circuit 399 can include an external TEC driver or anexternal conversion circuit that converts signals from the TEC driver316/356 to analog signals.

The primary FPGA 310 includes a pump driver 311, a TEC controller 315,and a TEC driver 316 integrated in the primary FPGA 310, and the TECcontroller 315 is internally coupled to (e.g., connected to) the TECdriver 316 in the primary FPGA 310. Similarly, the backup FPGA 350includes a pump driver 351, a TEC controller 355, and a TEC driver 356integrated in the backup FPGA 350, and the TEC controller 355 isinternally coupled to (e.g., connected to) the TEC driver 356 in thebackup FPGA 350. For its part, the laser pump being controlled by thecontrol system 300 has a pump chip 340 that includes a pump 341 and athermoelectric-cooler (TEC) 342 integrated in the pump chip 340.

An output terminal 312 of the pump driver 311 of the primary FPGA 310 iscoupled to an input terminal 321 of the DAC circuit 320, and an outputterminal 352 of the pump driver 351 of the backup FPGA 350 is coupled tothe input terminal 321 of the DAC circuit 320. An output terminal 322 ofthe DAC circuit 320 is coupled to the PUMP 341 integrated in the PUMPchip 340.

An output terminal 317 of the TEC driver 316 in the primary FPGA 310 iscoupled to the TEC 342 integrated in the pump chip 340 and an outputterminal 357 of the TEC driver 356 of the backup FPGA 350 is coupled tothe TEC 342 integrated in the pump chip 340. In some examples, theoutput terminal 317 of the TEC driver 316 in the primary FPGA 310 iscoupled to the TEC 342 via the external TEC driving circuit or externalconversion circuit 399; and the output terminal 357 of the TEC driver356 of the backup FPGA 350 is coupled to the TEC 342 via the externalTEC driving circuit or external conversion circuit 399; and the externalTEC driving circuit/external conversion circuit 399 coverts digitalsignals from the output terminal 317 of the TEC driver 316 or from theoutput terminal 357 of the TEC driver 356 to analog signals and providesthe analog signals to the TEC 342.

In the examples of FIG. 3, the backup FPGA 350 further includes afast-passive-parallel (EPP) driver 360 integrated in the backup FPGA350; and the backup FPGA 350 may be coupled to the primary FPGA 310 andmay perform fast FPGA reconfiguration on the primary FPGA 310 via theFPP driver 360. In some examples, the backup FPGA 350 may includeanother driver for performing FPGA reconfiguration, such as apassive-serial-configuration driver, and the backup FPGA 350 may becoupled to the primary FPGA 310 and may perform FPGA reconfiguration onthe primary FPGA 310 via the passive-serial-configuration driver. Inother examples, the FPGA reconfiguration on the primary FPGA 310 may beperformed by using some other component, e.g., a microcontroller unit(MCU), of the control system 300.

The control system 300 may further include a memory 305, e.g., forstoring or saving field content of the primary FPGA 310, e.g.,configuration data of the primary FPGA 310. The memory 305 may include,for example, an external synchronous dynamic random-access memory(SDRAM) that is external to, e.g., the primary FPGA 310; and/or aninternal random-access memory (RAM) of the backup FPGA 350; and/or anyother suitable memory device.

Again as will be appreciated, the arrangement depicted in FIG. 3 ismerely schematic. The pump chip 340 can have one or more pumps 341 andcan have one or more TEC devices 342 depending on the implementation.The control system 300 can be configured to operate the one or morepumps 341 and TEC devices 342 as needed.

In some examples, each of the pump drivers 311, 351 is configured todrive the pump 341 to produce optical output for a doped fiberamplifier, each of the TEC controllers 315, 355 is configured to controlthe TEC 342 to adjust a temperature of at least a portion of the pumpchip 340. In certain examples, the primary FPGA 310 has an operationmode and an update mode; the pump driver 311 of the primary FPGA 310 isconfigured to drive the pump 341 in the operation mode and to be atleast paused in the update mode; and the TEC controller 315 of theprimary FPGA 310 is configured to control the TEC 342 in the operationmode and to be at least paused in the update mode. In some examples, thepump driver 351 and the TEC controller 355 of the backup FPGA 350 areactivated in the update mode for the pump driver 311 and the TECcontroller 315 of the primary FPGA 310.

In some examples, the DAC circuit 320 is configured in the operationmode of the primary FPGA 310 to convert the drive from the pump driver311 of the primary FPGA 310 to the pump 341; and is configured in theupdate mode of the primary FPGA 310 to maintain the drive to the pump341 for the paused pump driver 311 of the primary FPGA 310, at leastuntil the pump driver 351 of the backup FPGA 350 is activated.

FIG. 5 illustrates a flow chart of an example control method 500 for anexample EDFA control system, such as shown in FIG. 3, including multipleFPGAs for uninterrupted light output according to disclosed embodiments.Via the control method 500, light output may be uninterrupted,e.g.,during upgrade of a primary FPGA. The control method 500 may beperformed via a control system/structure consistent with the presentdisclosure, such as the above described control system 300. Descriptionsfor the method 500 are made below with reference to FIGS. 3 and 5.

At S501 in FIG. 5, the pump driver 311 in the primary FPGA 310 ispaused. For example, the pump driver 311 in the primary FPGA 310 ispaused, and driver values of the pump driver 311 are kept the same,e.g., in DAC 320.

At S502, the TEC controller 315 in the primary FPGA 310 is stopped, andthe TEC controller 355 in the backup FPGA 350 is activated so thetemperature of the pump 341 is maintained. For example, the TECcontroller 315 in the primary FPGA 310 is stopped or deactivated, andmay be, for example, at a three-state mode or three-state logic foroutput (e.g., a high impedance state for output), so as to, e.g., notcontrol the TEC status from the TEC controller 315 in the primary FPGA310, and the TEC controller 355 in the backup FPGA 350 is activated, soas to maintain or control the temperature of the pump 314.

At S503, pump driver values i.e., pump drive values) of the primary FPGA340, e.g., pump driver values of pump driver of the primary FPGA, arecopied to the pump driver 351 in the backup FPGA 350, and the pumpdriver 351 in the backup FPGA 350 is activated or started.

At S504, field content (e.g., field data) of the FPGA (e.g., the primaryFPGA 310) is stored in a memory 305. For example, the field content ofthe primary FPGA 310 are stored in a memory 305. The memory 305 mayinclude, for example, an external synchronous dynamic random-accessmemory (SDRAM) that is external to, e.g., the primary FPGA 310; and/oran internal random-access memory (RAM) of the backup FPGA 350; and/orany other suitable memory device.

At S505, reconfiguration on the primary FPGA 310 is performed byactivating FPP configuration using the FPP driver 360, For example, theFPP driver 360 of the backup FPGA 350 may perform FPP configuration onthe primary FPGA 310, so as to reconfigure the primary FPGA 310.

At S506, the field content (e.g., field data) of the primary FPGA 350are restored. For example, the field content of the primary FPGA 310 maybe restored from the memory ## to the primary FPGA 310.

At S507, the control on the TEC 342 is returned to the primary FPGA 310.For example, the control on the TEC 342 is returned to the primary FPGA310.

At S508, the primary FPGA 310 is activated, and the update of drivervalues for the pump 341 is activated. For example, the primary FPGA 310is activated, and the primary FPGA 310 updates driver values for thepump 341 to DAC 320.

As noted, the memory 305 may include, for example, an externalsynchronous dynamic random-access memory (SDRAM) that is external to,e.g., the primary FPGA 310; and/or an internal random-access memory(RAM) of the backup FPGA 350; and/or any other suitable memory device.The field content/data of the FPGA (e.g., the primary or backup FPGA)may include, for example, present pump control values/set points, pumpdriver voltage/current, TEC control values, and driver values/set-pointsof optical components, including configuration values forvariable-optical-attenuator (VOA), optical photodiode, optical switch,etc.

Via the pump drive and control systems/structures of the presentdisclosure, the TEC driver or chip located outside the FPGA or outsidethe primary FPGA may maintain the drive control of the PUMP chip, whenthe FPGA or the primary FPGA needs to be updated. Accordingly,disturbance on existing tasks or services may be eliminated or reduced,when updating the primary FPGA or the backup FPGA. Thus, not only thescalability and expandability may be maintained, but alsomaintainability and upgradeability may be improved. In some examples, acontrol system having dual FPGAs may perform a fast FPP FPGAprogramming, and the upgrade time may be reduced to the order ofapproximately 20 ms.

The term “couple” or similar expression means either an indirect ordirect connection. If device A is coupled to device B, that connectionmay be through a direct connection or through an indirect connection viaother devices and connections.

The present disclosure may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive.

What is claimed is:
 1. A system for a pump chip of a doped fiberamplifier, the pump chip including a pump and a thermoelectric-cooler(TEC) device, the system comprising: a field-programmable gate array(FPGA) including a pump driver and a TEC controller, the pump driverconfigured to drive the pump to produce optical output for the dopedfiber amplifier, the TEC controller configured to control the TEC deviceto adjust a temperature of at least a portion of the pump chip; aconversion circuit coupling the drive of the pump driver of the FPGA tothe pump; and an external TEC driver being external to the FPGA andbeing coupled between the TEC controller and the TEC device, theexternal TEC driver being configured to control the TEC device in placeof the TEC controller.
 2. The system of claim 1, wherein the system isconfigured to: pause the pump driver, and keep driver values for thepump the same; and stop updating the external TEC driver, and cause theexternal TEC driver to take control on the TEC device.
 3. The system ofclaim 2, wherein the system is further configured to: store fieldcontent of the FPGA to a memory; activate FPGA reconfiguration; restorethe field content to the FPGA; return the control on the TEC device tothe TEC controller of the FPGA; and activate an update of driver valuesfor the pump.
 4. The system of claim 3, wherein the memory includes anflash-memory device external to the FPGA.
 5. The system of claim 3,wherein the field content of the FPGA includes at least one of controlvalues of the pump, drive values of the pump, TEC control values, orvariable-optical-attenuator configuration values.
 6. The system of claim1, wherein the FPGA has an operation mode and an update mode, the pumpdriver being configured in the operation mode to drive the pump andbeing at least paused in the update mode, the TEC controller beingconfigured in the operation mode to control the TEC device and being atleast paused in the update mode.
 7. The system of claim 6, wherein theconversion circuit is configured in the operation mode to convert thedrive from the pump driver to the pump and is configured in the updatemode to maintain the drive to the pump for the paused pump driver. 8.The system of claim 6, wherein the external TEC driver is configured inthe operation mode to drive the TEC device based on the control of theTEC controller and is configured in the update mode to control the TECdevice for the paused TEC controller.
 9. The system of claim 1, whereinthe system comprises the pump chip including the pump and the TECdevice.
 10. A system fora pump chip of a doped fiber amplifier, the pumpchip including a pump and a thermoelectric-cooler (TEC) device, thesystem comprising: a primary field-programmable gate array (FPGA)including a primary pump driver, a primary thermoelectric-cooler (TEC)controller, and a primary TEC driver; a backup FPGA disposed incommunication with the primary FPGA and including a backup pump driver,a backup TEC controller, and a backup TEC driver, each of the pumpdrivers configured to drive the pump to produce optical output for thedoped fiber amplifier, each of the TEC controllers configured to controlthe TEC device to adjust a temperature of at least a portion of the pumpchip; a first conversion circuit coupling the primary and backup pumpdrivers to the pump; and a second conversion circuit coupling theprimary and backup TEC controllers to the TEC device.
 11. The system ofclaim 10, wherein: the backup FPGA further includes afast-passive-parallel (FPP) driver; and the backup FPGA is coupled tothe primary FPGA via the FPP driver.
 12. The system of claim 10, whereinthe system is configured to: pause the primary pump driver in theprimary FPGA; stop the primary TEC controller in the primary FPGA, andactivate the backup TEC controller in the backup FPGA; and copy a pumpdriver value of the primary FPGA to the backup pump driver in the backupFPGA, and activate the backup pump driver in the backup FPGA.
 13. Thesystem of claim 12, wherein the system is further configured to: storefield content of the primary FPGA to a memory; reconfigure the primaryFPGA; restore the field content of the primary FPGA; return control onthe TEC of the pump chip to the primary FPGA; and activate the primaryFPGA, and active update of the pump driver value for the pump.
 14. Thesystem of claim 13, wherein: the backup FPGA further includes afast-passive-parallel (FPP) driver; the backup FPGA is coupled to theprimary FPGA via the FPP driver; and 7 the backup FPGA is configured toreconfigure the primary FPGA by using the fast-passive-parallel (FPP)driver.
 15. The system of claim 13, wherein the memory includes at leastone of a synchronous dynamic random-access memory (SDRAM) external tothe primary FPGA or a random-access memory (RAM) of the backup FPGA. 16.The system of claim 13, wherein the field content of the FPGA includesat least one of control values of the pump, drive values of the pump,TEC control values, or variable-optical-attenuator configuration values.17. The system of claim 10, wherein the primary field-programmable gatearray (FPGA) has an operation mode and an update mode, the primary pumpdriver being configured in the operation mode to drive the pump andbeing at least paused in the update mode, the primary TEC controllerbeing configured in the operation mode to control the TEC device andbeing at least paused in the update mode; and wherein the backup pumpdriver and the backup TEC controller of the backup FPGA are activatedfor the primary pump driver and the primary TEC controller of theprimary FPGA in the update mode.
 18. The system of claim 17, wherein thefirst conversion circuit is configured in the operation mode of theprimary FPGA to convert the drive from the primary pump driver to thepump; and wherein the first conversion circuit is configured in theupdate mode of the primary FPGA to maintain the drive to the pump forthe paused primary pump driver at least until the backup pimp driver isactivated.
 19. The system of claim 17, herein the backup FPGA comprisesa fast-passive-parallel driver (FPP) disposed in communication with theprimary FPGA, the backup FPGA being configured to perform fast FPGAreconfiguration on the primary FPGA via the FPP driver.
 20. A methodused for a pump chip of a doped fiber amplifier, the pump chip includinga pump and a thermoelectric-cooler (TEC) device, the method comprising:driving, by a pump driver of a field-programmable gate array (FPGA), thepump to produce optical output for the doped fiber amplifier in anoperation mode; controlling, by a TEC controller of the FPGA, the TECdevice to adjust a temperature of at least a portion of the pump chip inthe operation mode; pausing the pump driver of the FPGA, andmaintaining, via a conversion circuit external to the FPGA, driving onthe pump for the paused pump driver in an update mode; pausing the TECcontroller of the FPGA, and controlling, by an external TEC driver withrespect to the FPGA, the TEC device for the paused TEC controller in theupdate mode.
 21. The method of claim 20, further comprising performingreconfiguration on the FPGA in the update mode.
 22. A method used for apump chip of a doped fiber amplifier, the pump chip including a pump anda thermoelectric-cooler (TEC) device, the method comprising: driving, bya primary pump driver of a primary field-programmable gate array (FPGA),the pump to produce optical output for the doped fiber amplifier in anoperation mode; controlling, by a primary TEC controller of the primaryFPGA, the TEC device to adjust a temperature of at least a portion ofthe pump chip in the operation mode; pausing the primary pump driver ofthe primary FPGA, and activating a backup pump driver of a. backup FPGAto driver the pump to produce the optical output for the doped fiberamplifier in an update mode; and pausing the primary TEC controller ofthe primary FPGA, and activating a backup TEC controller of the backupFPGA to control the TEC device in the update mode.
 23. The method ofclaim 22, further comprising performing, by a fast-passive-paralleldriver in the backup FPGA, reconfiguration on the primary FPGA in theupdate mode.